Strap-stretching device



April 1, 1930. c. M. MacCHESNEY El l- STRAP STRETCHING DEVICE 2 Sheets-Sheet 1 Filed Oct. 26, 1925 April 1, 1930. c. M. M cHEsNEY STRAP STRETCHING DEVICE Filed Oct. 26, 1925 2 Sheets-Sheet 2 Q Q N Nu @DN -..V W 1 w A m x '&

Patented Apr. 1, 1930 UNITED STATES PATENT OFFICE CHESTER M. MACCHESNEY AND RALPH H. NORTON, OF CHICAGO, ILLINOIS, ASSIGNORS TO ACME STEEL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS srner-srnnrcnme :onvron Application filed October 26, 1925. Serial No. 64,732.

This invention relates to an invention in strap stretching devices and its purpose is to provide improved means for tightening and stretching a metal strap or the like when applied to a box or other object. The principal object of the invention is to provide a device which is capable of being conveniently and eiiiciently manipulated for gripping the ends of the metal strap and tightening the straparound a box or the like preliminary tosecuring the ends of the strap by suitable fastening means. A further object is to provide a hand operated strap tightening device comprising improved means for effecting relative movement of the ends of'the strap. A further object is to provide a hand operated strap tightening device having strap stretching means and strap gripping means which may be conveniently manipulated by the hand of the operator. Other objects relate to various features of construction and arrangement which will appear more fully hereinafter.

The nature of the invention will be understood from the following specification taken with the accompanying drawings in' which one embodiment is illustrated. In the drawings, Figure 1 shows atop plan View of the improved strap stretching device; Fig. 2 shows a sideflelevation of the deviceyillustrating the use of the invention in applying a strap to a box; Fig. 3 shows a side elevation of a portion of the device, looking toward the side thereof opposite that illustrated in Fig. 2, a part of the casing or frame being broken away to illustrate the interior construction; Fig. 4 shows a detail section taken onthe line 4-4 of Fig. 3, looking in the direction of the arrows; Fig. 5 shows a bottom plan view of a portion of the strap stretching device; and Fig. 6 is a sectional view taken on the line 66 of Fig. 3, looking in the direction of the arrows.

The invention comprises a frame member 10, formed preferably as an integral casting out of bronze or the like, and provided on its under side with a longitudinal groove or guideway 11 in which is mounted a rack bar 12 of rectan ular cross section. The

dle portion 14 to be engaged by the hand of the operator and an integral lug 15 extends upwardly at the forward end of the handle 14 to engage the operators hand between the thumb and fore finger during the operation of the device. The guideway 11 extends throughout the length of the handle 14 and the rear portion of the rack bar 12 extends beneath the lower edge of the handle,

as shown in Fig. 2. The rack bar is provided on its under side throughout the major portion of its length with rack teeth 12- adapted to be engaged by the mechanism hereinafter described for effecting relative movement of the rack bar and the frame 10 during the operation of tightening and stretching a strap.

The rack bar 12 is provided at its forward end with a head 16, secured thereto by rivets 17. or the like and this head carries a relatively fixed base plate 18, secured thereto by rivets 18 or the like which projects laterally from one side of the head and is adapted to rest on the top surface of a box 19 or the like during the operation of tightening and stretching a metal strap 20 around the box, as illustrated particularly in Fig. 2. The projecting portion of the base plate 18 is provided with an aperture which is threadedly engaged by an adjustable and removable gripping member 21 having a serrated top surf ce 21 adapted to engage the under side of one end portion 20' ofthe metal strap, the extreme end of the strap being extended over a boss 22 V -21 having an enlarged head adapted to engage in one of a plurality of notches 21 which are formed in the end of the member 21, as shown in Fig. 5. The head 16 is provided above the plate 18 with a tranverse slot 23 which is loosely engaged by an upper movable gripping member 24 having a projection 24: extending laterally and adapted to contact with the upper side of the end portion 20 of the strap. This upper gripplng member 24 is held in position 1n the slot 23 by means of a screw 25 extending upwardly through the base plate 18 and loosely engagtie ing an aperture 26 which extends vertically through the member 24-, as illustrated in Fig. l. The screw 25 holds the member 24; in substantially fixed relation to the head 16 but permits it to rock vertically to permit a gripping pressure to be exerted on the strap 20 by the operation of a cam 27 which is formed as a part of the hub of an operating lever 28 pivoted on a pin 29 extending laterally from the head 16. The hub of the lever 28 is provided with a shoulder 30 adapted to be engaged by a pin 31, secured to the side of the head 16, for the purpose of limiting the movement of the lever 28 upwardly from the strap gripping position illustrated in Fig. 2. Vl/hen the lever 28 is in its lower position, the cam 27 forces the upper gripping member 2% downwardly, thereby holding the free end of the strap in fixed position with respect to the strap stretching device. The lever 28 is normally forced toward its upper or released position by the action of a coil spring 32 which is mounted on the pivot pin 29 with one end thereof fixed in an aperture 33 in the hub of the lever and with the other end secured to the cotter pin 34; by which the lever and spring are retained in position on the pin 29.

The upper surface 24 of the projecting portion of the upper gripping member 24 is inclined upwardly away from the boss 22 and after the strap 20 has been extended around the box 19, it is carried over the inclined surface 24: and thence toward the right, as viewed in Fig. 2, to be engaged by other gripping means carried by the frame 10. For this purpose, the frame 10 is provided at its forward end with a laterally projecting head 35 provided at its lower edge with a laterally in'ojecting foot piece 36 having an aperture therein which is threadedly engaged by a detachable gripping member .37, similar to the gripping member 21., its upper surface being serrated to engage the under side of the por tion 20 of the metal strap. This gripping member is retained in position by means of a locking screw 38 having an enlarged head adapted to engage one of the recesses 37 formed in the gripping member 37, as shown in Fig. 5. The portion 20 of the strap is secured in contact with the fixed gripping member 37 by means of a cam 39 formed on the hub of an operating lever l0 which is pivoted on a pin 41 extending laterally from the head 35. The movement of the lever upwardly from the locking position illustratcd in Fig. 2, is limited by a pin 42 adapted to engage a shoulder 4-3 formed on the hub of the lever, and the lever is normally forced in this upward direction by means of a coil spring 4% mounted on the pin tl. One end of the coil spring 44 is secured in an aperture 45 formed in the hub of the lever and the other end of the spring is secured to the cotter pin 16 by which the spring and the lever are retained in position on the pin l. The lever area 40 extends parallel to the longitudinal axis of the frame 10 and, when in its lower position, is adapted to lie alongside the frame member, while the lever 28 is directed inwardly over the frame 10, as shown in Fig. 1, so that either of the levers may be conveniently engaged by the thumb of the operator when the device is in operation. When the levers 28 and 40 are in their locking positions, the pressure exerted by the cams 27 and 39 will be sufficient to retain the levers in their lower positions against the action of the springs 32 and 44:, but a slight initial upward pressure imparted to the lovers 28 and 40 serves to bring the springs into operation and to carry the levers into their uppermost positions determined by the pins 31 and 42.

Having applied the strap 20 to the box 19 and secured the end portions'of the strap to the heads 16 and 35 by manipulating the levers 28 and 40, respectively, the operator tightens the strap around the box by eilecting a movement of the head 35 and the frame 10 away from the head 16 which may remain stationary on the top surface of the box or have a limited movement thereon. This relative movement of the heads 16 and 35 is effected by a pawl or detent mechanism operated by a finger lever pivoted on a pin 51 extending between the side walls 52 of the guideway 11, these side walls being extended downwardly between the handle and the head 35, as illustrated in Fig. 2. The finger lever 50 is provided with an angularly disposed crank 53 extending upwardly be tween the side walls 52 and pivotally connected at its upper end by a pin 5% to a pawl 55 having a tooth 55 adapted to engage the teeth 12 of the rack bar 12. The pawl 55 has a pin 56 secured to the side thereof adjacent the tooth 55 and extending outwardly through an opening 57 formed in one of the side walls 52 of the frame member 10. This pin 56 is provided with a transverse aperture 56 which is loosely engaged by a rod 58 having formed thereon a collar 58 adapted to seat against the pin 56, as illustrated in Fig. 3. The rod 58 slidably engages an aperture in another pin 59 which extends laterally from the lower forward corner of the frame 10, opposite the head 35. A coil spring 60 is mounted on the rod 58 and tends normally to force the pawl 55 toward the left, as viewed in Fig. 3, with a resulting downward movement of the finger lever .50. During this movement of the pawl 55 and the lever 50 the tooth 55 of the pawl slides over the inclined face or faces of one or more of the rack teeth 12, thus placing the parts in position for the next succeeding operation of the lever 50 in effecting a separation of the heads 16 and 35 to which the ends of the strap are attached. The spring 60 serves also to main tain the pawl 55 in engagement with the rack bar and it will be apparent that the upward movement of the lever 50 operates to force the frame 10 and the head 35 toward the left, as viewed in Fig. 3, the head 16 of small area then resting on the surface of the box. The upward movement of the lever 50 is limited by an adjustable stop screw 61 held in posi; tion on the lever by a nut 62 and adapted, when'the lever is in its uppermost position, to engage a filler block 63 which is secured between the side walls of the guideway 11 to support the rack bar 12 adjacent the handle 14. The forward portion of the rack bar is maintained in engagement with the guide way by another filler block 64 secured between the forward portions of the side walls 52.

After the lever has been manipulated to effect a movement of the frame 10 with respect to the head 16, these parts are maintained in the new relative position, during the downward movement ofthe lever 50, by the operation of a detent 65 having a tongue 65 which extends between the wings 50 of the lever 50 and is pivoted on the pin 51. The detent 65 is maintained in engagement with the rack teeth 12 by means of a coil spring 66 mounted on the stem of the pin 59 between the side walls 52, and having an arm 66 extending longitudinally therefrom to contact with the under side of the detent.

This compact arrangement of the operating mechanism of the strap adjusting device makes it possible for the operator to apply the strap 20 to the device with great convenience when the base plate 18 is resting on the top surface of the box, the strap being placed in position with one hand while the other hand engages the handle 14:. The strap is preferably drawn as tightly as possible around the box by the hand of the operator after the lever 28 has been manipulated to effect the gripping of one end of the strap and before the other thumb lever 40 is manipulated to grip the portion 20 of the strap. The heads 16 and 35 are then in close proximity to each other and after operating the lever 40 to grip the supply end of the strap, the finger lever 50 is manipulated a sufficient number of times to draw the strap 20 tightly about the boX, the limit of the relative movement of the head 16 and the frame 10 being determined by a stop member 68 which extends downwardly from the under side of the rack bar 12 in the path of relative movement of the filler block 63. After the desired degree of tautness is secured in the metal strap 20, the adjacent or overlapping portions thereof may be secured to each other at the point 69 by a suitable fastening device or by welding or the like and, upon releasing the levers 28 and 40, the base plate 18 may be caused to slide out from position beneath the strap, sufficient tension being provided in the strap to compensate for the removal of this plate from its position beneath the strap,

whereby the strap remains in tight engagement with all of the walls of the box.

Although one form of the invention has been shown and described by way of illustration, it will be understood that it may be constructed in various other embodiments within the scope of the appended claims.

We claim:

1. A device for holding and stretching a strap comprising a frame member, a rack bar mounted in said frame member and having relative movement, longitudinally thereof, separate gripping means carried by said rack bar and by said frame member for engaging the ends of a strap, a lever pivoted on said frame member, a pawl pivoted on said lever and arranged to engage said rack bar, and resilient means attached to said frame and connect-ed to said pawl for normally moving said lever away from said frame member and simultaneously moving said pawl away from said rack bar.

2. A device for holding and stretching a strap comprising a frame member, a rack bar mounted in said frame member and having relative movement longitudinally thereof, separate grouping means carried by said rack bar and by said frame member for engaging the ends of a strap, a lever pivoted on said frame member, a pawl pivoted on said lever and arranged to engage said rack bar, resilient means attached to said frame and connected to said pawl for normally moving said lever away from said frame member and simultaneously moving said pawl away from said rack bar, and a detent mounted independent ly of said pawl and actuated normally to engage said rack bar.

3. A device for holding and stretching a strap, comprising a frame member, arack bar movable longitudinally of said frame member, gripping means carried by said rack bar, other gripping means carried by said frame member, a lever pivoted on said frame member, a pawl actuated by said lever for engaging said rack bar, and means tending normally to return said pawl and said lever to their inoperative positions.

4. A device for holding and stretching a strap, comprising a frame member, a rack bar movable longitudinally of said frame member, gripping means carried by said rack bar, other gripping means carried by said frame member, a lever pivoted on said frame member, a pawl actuated by said lever for engaging said rack bar, and resilient means coacting with said pawl for efiecting movement of said pawl and said lever to their inoperative positions.

5. A device for holding and stretching a strap, comprising a frame member prov ded with a handle and having a longitudinal groove in its under side, a rack bar slidably rack bar for engaging a strap, a finger lever pivoted on said frame member beneath said rack bar handle, said finger lever having a crank, a pawl pivoted on said crank and adapted to engage said rack bar, and means connecting said pawl with said frame memher for effecting a return movement of said pawl and said finger-lever after said lever has been moved toward said frame member.

6. A device for holding and stretching a strap, comprising a head having a base plate, said head being provided with a transverse slot extending parallel to said base plate, a non-rotatable gripping member loosely mounted in said slot and having a part extending over said base plate, a cam adapted to engage the upper side of said gripping member, and means for operating said cam.

7. A device for holding and stretching a strap, comprising a frame member provided with a handle, a lug extending upwardly at the forward end of said handle, a bar slidabl'y mounted in said frame member, gripping means carried at the forward end of said bar, other gripping means carried at the forward end of said frame member, actuating means for said gripping means comprising levers extending rearwardly toward said handle, mechanism for effecting relative movement of said gripping means, and a lever pivoted on said frame member bereath said handle for operating said mechanism.

8. A strap holding and stretching device comprising a frame member, a bar mounted for movement on said frame member, a pair of gripping means, one of which is mounted on said bar and the other on said frame memher for engaging opposite end portions of a strap, means carried by one of said gripping means for permitting the body portion of said strap to pass thereover in overlapping contaeting relation to one extremity of said strap, means mounted adjacent said last named gripping means for holding said extremity of said strap in engagement with said body portion of said strap, and means carried by said frame member for efiecting relative movement of said frame member and said bar to separate said gripping means.

CHESTER M. MAGCHESNEY.

RALPH H. NORTON.

weaaee CERTIFICATE OF CORRECTION.

I Patent No. 1,752,495. Granted April 1, 1930, to

CHESTER M. MacCHESNEY ET It is hereby certified that error appears in the printed specification of the above numbered patent requiring correetion as follows: Page 3, line 92, claim 2, for the word "grouping" read "gripping"; page 4, line 3, claim 5, strike out the words "rack bar"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Cities.

Signed and/sealed this 13th day of May, A. D. 1930.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

